Method of and apparatus for the electrostatic curing of heat curable materials, while under pressure



y 19 c. E. BENNETT 2,282,317.

METHOD OF AND APPARATUS FOR THE ELECTROSTATIC CURING OF HEAT CURABLE MATERIALS WHILE UNDER PRESSURE Filed Dec. 51, 1940 ATTORNEYS Patented May 12, 1942 METHOD OF AND APPARATUS -FOR THE ELECTBOSTATICCURING OF HEAT CUR- WHILE UNDER PRES- ABLE MATERIALS, SURE Charles E. Bennett, Bldgewood, N. 1., assignor to The Okonite Company, Panel poration or New Jersey Application December 31, 1940, Serial No. 372,694

.4Claims.

This invention relates to an improved method and apparatus for the electrostatic curing of rubber and rubber-like materials, plastics, etc., and has for its .primary object the provision of means whereby the material to be cured is subc, N. 1., a corvaried over'a wide range up to hundreds of pounds to the square inch.

While the ability to-maintain high pressures 2 on the insulation during the curing stage is of jected to fluid pressure during the curing operation.

The accompanying. drawing illustrates one embodiment of my invention as applied to the curing of the insulation of insulated conductors.

Referring to the drawing in detail: 2 designates a reel of bare wire which is to be" insulated with any suitable rubber compound, the insulation thereafter to be electrostatically vulcanized with the wire in motion and while the insulation is maintained under pressure.

4 designates the apparatus for applying the insulation. This may be the usual extruding mechanism employed in the art of insulating conductors. It is obvious that the wire 2 as it emerges from the mechanism 4 has been insulated with an uncured insulating material.

6 designates a pressure cylinder of porcelain, for instance, or other insulating material sufflciently strong to withstand pressures of several hundred pounds.

Each end oi this pressure cylinder 8 is equipped with a stufiing box 8. The insulated wire which I have designated In, it is understood, passes continuously through the pressure cylinder, and in order that the insulation will not be injured and that the insulated wire may be moved with the minimum of'eiiort the stuffing boxes 8 are not leakproof flt on the wire.

Oil or other electrically conducting medium is supplied to the pressure cylinder by supply pipe ll which is connected to any suitable pressure supply source.

As above mentioned the stumng boxes I are a loose flt upon the insulated wire, and in order that the conducting fluid I! may not escape and may be maintained under pressure suitable conduits l6 communicate with the stufllng boxes, these conduits being connected to a suitable source or compressed air.

paramount importance, it will be appreciated also that by reason of the balanced condition oi the system anly the minimum effort is required to advance the conductor assembly.

A high frequency source of electrical energy has been diagrammatically indicated at IS. The bare wire 2 constitutes one electrode of this system, the conducting fluid I! the other electrode.

It will be seen from all of the foregoing that in accordance with this invention the material to be cured is passed continuously through a pressure cylinder while being subjected to the influence of an electrostatic field.

It will be understood that this air pressure subcontinuously through the pressure cylinder, is

eliminated, enabling the insulation to be maintained under high pressure during the curing operation. The pressures employed may be It is to be understood that changes may be made in the details of the apparatus above described without departing from the spirit and scope of the invention.

What l2 claim is:

1. The method of heat curing materials while maintaining-the same under pressure, which method comprises subjecting the material to the influence of an electrostatic fleld while the material is being moved through a pressure chamber containing a pressure fluid in which the material is submerged and while preventing loss of pressure fluid from the chamber past the material as the same passes into and out of the chamber by maintaining the chamber at the points of entrance and exit of the material in communication with an outside source of fluid supply at a pressure which is as high as that of the flrst mentioned pressure fluid and directed inwardly of the chamber.

2. An apparatus for the heat curing of materials comprising in combination a pressure chamber, a fluid in said chamber, means for maintaining the fluid under pressure, stufling boxes at the ends of the chamber for permitting of the continuous passage through the chamber of the material to be cured into and out of the chamber, and pressure supply means connected to said stufling boxes for imposing pressure on the fluid in the chamber through the stuiiing boxes in a direction inwardly oi the chamber, the last mentioned pressure being at least as high as the pressure at which the fluid in said chamber is maintained.

8. An apparatus for the heat curing of materials comprising in .combination a pressure chamber containing a liquid, means for maintaining said liquid under pressure, a stufling box at eachend of the chamber for permitting oi the continuous passage through the chamber or the material to be cured, and air pressure supply means connected to each 01' said stumng boxes for sealing the stufling boxes against the escape or fluid from the pressure chamber.

4. An apparatus for the heat curing of materials comprising in combination a pressure chamber, an electrical conducting liquid in the chamber, means for maintaining said liquid under pressure, a stufllng box at each end of the pressure chamber for permitting of the continuous passage through the chamber of an insuits insulation will be subjected to pressure while under the influence of an electrostatic iield.

CHARLES E. BENNETT. 

